As shown in FIG. 1, the conventional printed circuit is made of PET or PI boards (films) which is made as a substrate 10′. Then a metal layer 30′ is adhered to the substrate 10′ by using an adhesive layer 20′. Material of the metal layer 30′ is selected from copper, silver, gold, etc. If packaging is necessary, silicon 40′ is added to the printed circuit.
Generally, printed circuits are classified as hard boards and soft boards. The hard boards are made of FR4, aluminum, or ceramics. The soft boards are made of PET, PI, etc. The structure of soft boards has some defects in practical usages. The main reasons are that PET or PI are not usable in high temperatures over 130° C. This high temperature will induce deformation of the circuit or the electric properties of the elements on the circuit boards are shifted, for example, impedances are changed so that precise data transfer cannot be achieved.
The extension property of PET or PI is not preferable. In many applications, for example, biological chips, these circuit boards are not suitable due to bad extension property. Furthermore PET or PI boards are not compactable biologically. The boards are easily reacted with peripheral organs biologically.
Therefore, the present invention desired to provide a novel invention which can improve above mentioned defects.